Heart failure is the pathophysiological state in which heart is unable to pump blood at a rate commensurate with the requirement of the metabolizing tissues or can do so only from an elevated filling pressure (increased load). With time when this condition leads to excess fluid accumulation such as peripheral edema it is referred to as congestive heart failure.
When an excessive pressure or volume load is imposed on the ventricle myocardial hypertrophy develops, providing a compensatory mechanism that permits the ventricle to sustain an increased load. However, a ventricle subjected to an abnormally elevated load for a prolonged period may fail to maintain compensation despite the presence of ventricular hypertrophy and pump failure may ultimately occur.
Hypertension is defined as an increase in resistance to blood flow through the vascular system. This resistance leads to increases in systolic and or diastolic blood pressures. Hypertension places increased tension to the left ventricular myocardium, causing it to stiffen and hypertrophy and accelerate the development atherosclerosis in the coronary arteries. The combination of increased demand and lessened supply increases the likelihood of myocardial ischemia leading to myocardial infarction, sudden death, arrhythmias and congestive heart failure.
Ischemia is defined by an organ or a part of the body failing to receive a sufficient blood supply. An organ that is deprived of a blood supply is said to be hypoxic. An organ will become hypoxic even when the blood supply temporarily ceases, such as during a surgical procedure or during temporary artery blockage. Ischemia leads to structural and functional abnormalities, such as arrhythmias, cell death and ventricular remodeling. When the organ affected is the heart this condition is known as ischemic heart disease.
When blood flow resumes to an organ after temporary cessation, this is known as ischemic reperfusion of the organ. Ischemic reperfusion to an organ also leads to injury of the organ by producing structural and functional abnormalities in the tissue of the organ. Conditions observed with ischemia reperfusion injury include neutrophil infiltration, and necrosis.